Development of a head module for multi-head Si/CdTe Compton camera

Yamaguchi, Mitsutaka; Kamiya, Tomihiro; Kawachi, Naoki; Suzui, Nobuo; Fujimaki, Shu; Odaka, Hirokazu*; Ishikawa, Shinnosuke*; Kokubun, Motohide*; Watanabe, Shin*; Takahashi, Tadayuki*; Shimada, Hirofumi*; Arakawa, Kazuo*; Suzuki, Yoshiyuki*; Torikai, Kota*; Yoshida, Yukari*; Nakano, Takashi*

We are constructing a three-dimensional imaging system for medical and biological applications as a device that can provide simultaneous imaging, having high spatial and energy resolutions and wide energy range from several tens keV to a few MeV, by diverting the most advanced space-observation technology, Si/CdTe semiconductor Compton camera, developed in ISAS/JAXA. The Si/CdTe Compton camera was developed under the assumption that the use of moderate temperature and the Analog ASIC for signal processing. Moreover, because the solid and thin scattering layer allows close placement of the measured object, good angular resolution corresponds to good spatial resolution directly. These aspects allow construction of compact medical system. In contrast to space-observation use, three-dimensional imaging ability becomes important for life science research. In order to achieve a good three-dimensional spatial resolution, modularizing the Compton camera into a small camera head and allowing multi-angle imaging with multi-head structure is required. In this work, a head module has been developed as a prototype module of the multi-head system. Sensor and circuit modules are closely arranged and put in a compact vacuum-insulating cylindrical housing. Each of camera heads will be fixed on robot arms and be able to adjust the positions and the directions. Performance evaluation test was made for the prototype module with a sealed Ba-133 radiation source. We confirmed that the imaging result is consistent with the source positioning. The angular resolution measure, abbreviated as ARM, was estimated to be 4.5 degree. The result of the test was compared with a Monte Carlo simulation study. We will report the details of the prototype module and the result of the performance evaluation test. The expecting three-dimensional performance will also be reported.